During the era of the Protoss Empire, Khalai Caste scientists were ordered by the Conclave to create the ultimate mechanical warriors. This force would consist of approximations of some of the greatest warriors in protoss history. From this came the Purifiers, automatons with decision-making capabilities that were often 99.3% accurate to the protoss subject the replication was patterned after.[1]

However, the Conclave did not treat the Purifiers as equal to other protoss, rather seeing them as tools to be used. Seeing the Conclave as slave masters, the Purifiers rebelled against their creators,[2] led the purifier reconstruction of Executor Clolarion.[3] The resulting conflict claimed many protoss lives, notably destroying all protoss stationed in Lantinum.[4] However, the Purifiers were defeated by the greater Protoss Empire forces, and forced into submission.

The Purifiers were sealed within the platform of Cybros, and put into stasis above the world of Endion.[1] The Conclave declared the creation of any more Purifiers to be heresy.[5]Cybros and the Purifiers within served as a symbol of protoss achievement, but also the dangers of it.[6]

During the End War, Cybros was unsealed and the ancient Purifiers within were reactivated by HierarchArtanis. Due to the Purifier Rebellion, Grand PreserverRohana expressed great concern for the dangers reactivating the Purifiers presented.[4] The ancient Purifiers who fought in the rebellion meanwhile approached the Daelaam with initial mistrust, not forgetting their treatment at the hands of the Conclave.[7]